The region from Egypt to the United Arab Emirates has been suffering from a blistering heat wave this summer, putting stress on power grids and challenging even the locals who are accustomed to the intense heat. Temperatures in recent weeks have been well above normal, topping out at 111 degrees in Bahrain, 115 in Abu Dhabi and 129 in Oman. Water, which is stored atop roofs, needs to be cooled rather than heated for morning showers.